"Selenium enrichment" refers to selenium rich in trace elements. Selenium is an essential trace element for human body. Selenium participates in the synthesis of various selenium-containing enzymes and selenium-containing protein in human body. Among them, glutathione peroxidase catalyzes the conversion of hydroperoxide or lipid peroxide into water or various alcohols in organisms, eliminating the attack of free radicals on biofilm and protecting biofilm from oxidative damage; Selenium participates in the formation of iodothyronine deiodinase. There are many foods in the domestic market under the banner of selenium enrichment. Selenium can improve human immunity, promote lymphocyte proliferation and synthesize antibodies and immunoglobulins. Selenium has obvious inhibitory and protective effects on colon cancer, skin cancer, liver cancer, breast cancer and other cancers, and its intermediate metabolite methyl enol in the body has strong anticancer activity. Nutrients such as selenium, vitamin E, allicin, linoleic acid, germanium and zinc have synergistic antioxidant effect and increase antioxidant activity. At the same time, selenium can reduce and alleviate the toxicity of heavy metals.